Warm air furnace



2 Sheets-Sheet v1 C. B. LOCKHART WARM AIR FURNACE Filed Jan. 8, 1935 INVENTOR.

Nov. 17, 1936.

ATTORNEY Nov.17,1936. C BLOCKHART 2,061,284

WARM AIR FURNACE Filed Jan. 8, '1955 2 sheets-sheet 2 NVENTOI? WQLMLA TToRNEY Patented Nov. 17, 1936 UNHTED STATES PATENT @FFHE 2 Claims.

This invention relates to warm air furnaces, and more particularly to a warm air furnace having means for directing or controlling the distribution of the air which is circulated through the furnace.

The principal object of this invention is to intercept radiant heat from the furnace to prevent loss thereof to the outer casing.

A further object is to provide uniform impingement of air on the heated surface of the furnace to secure efficient heating thereof.

With the foregoing and other objects in view which will appear as the description proceeds, the invention resides in the combination and arrangement of parts and in the details of construction hereinafter described and claimed, it being understood that changes in the precise embodiment of the invention herein disclosed, can be made within the scope of what is claimed, without departing from the spirit of the invention.

The invention is illustrated in the accompanying drawings, wherein:-

Figure 1 represents a side elevation of a conventional warm air furnace having a blower for supplying cold air thereto and having a wind box construction embodying my invention.

Figure 2 is a horizontal sectional View in the plane of line 2 2 of Figure 1.

Figure 3 is a transverse vertical section through the construction shown in Figure 1.

Figure 4 is a similar section in a plane at right angles to the section of Figure 3 and with the inner furnace structure removed.

The general construction of the furnace is that of any known or preferred warm airfurnace, and the drawings illustrate the furnace construction per se more or less conventionally, such accessories as grate bars, refractory linings, etc., being omitted.

In the drawings, 2 designates more or less conventionally the shell of the inner furnace structure, this shell forming the combustion unit inside which the fuel is burned. The ring door through which the fuel is charged into the combustion chamber is indicated at 3. At the top of the unit 2 is a pipe 4 to which is connected a hollow casing 5, this casing being known in the art as a radiator, and providing for the circulation of hot gases of combustion after they leave the combustion chamber and before they enter the ue pipe, which flue pipe is designated 6.

As previously indicated, the entire arrangement is of the conventional form well-known to those skilled in the art. Surrounding the inner furnace unit 2 with its radiator 5 is an outer shell 1, also of conventional form, this shell being spaced a considerable distance from the walls of the inner furnace 2 to provide an air space S all the way around the structure 2. This casing is provided with a top 9 in which we have indicated hot air discharge pipes Ill for conducting the warm air to different parts of the building or structure to be heated.

Interposed between the outer casing i and the inner furnace structure 2 is a shield or screen i i, also formed of thin sheet metal, and which extends from a point approximating the lowest point of the fire box in the chamber 2 to a point adjacent the top of the structure 2, the purpose of this shield being to intercept heat waves radiated from the outside of the structure 2 and prevent this heat from impinging on the outer shell l. The arrangement is such that air can circulate inside and outside this screen II. The inner furnace structure 2 is preferably provided withsupporting legs I2 so that its bottom is spaced above the floor at I3 on which the furnace is set.

For introducing the air to be heated into the furnace, I provide in the lower part of the furnace a conduit or wind box, designated generally as I4, this box having a rear portion I 4d (see Fig. 2) which is located under the radiator 5 and which extends around the back of the furnace structure 2. It is provided with forwardly extending leg portions Mb that extend around the sides of the inner structure 2 and forwardly alongside the wings or pockets at the front of the structure 2. The portion I 4a has a series of openings therein, these openings being designated I5, so positioned as to discharge air directly against the bottorn and sides of the radiator 5. The wind box structure is spaced a slight distance away from the lower part of the furnace structure 2, and it has a baffled or sloping surface I6, this sloping surface being also formed on the leg portions |473. In this sloping surface are a series of openings il so that air discharging from the openings Il will be blown inwardly and upwardly against the structure 2. The openings I'l are located in the approximate plane of the bottom of the re box in the structure 2 and above the plane of the ash pit, so that the air will impinge against that portion of the inner furnace structure 2 which is subject to the greatest heat. The wind box may also be provided adjacent its bottom with one or more openings I8 through which air may be discharged to flow under the bottom of the inner furnace structure 2, this air then owing upwardly through the space I9 between the wind box and the inner furnace structure 2 to mingle with the air in the air space above the wind box. A pipe 20 leads from the back of the wind box to a fan unit 2 I, the fan unit being more or less conventionally illustrated.

The various openings provided in the wind box structure for the discharge of air therefrom are located and positioned in such manner as to give the most eective distribution of the air flow, and they may be proportioned in such manner as to give the desired distribution of air to different parts of the furnace, as the construction of a particular furnace may require. Moreover, the total area of these openings is preferably such as to cause the fan to maintain a slight pressure in the Wind box so that the air discharging through the ports will be discharged with an appreciable Velocity and by reason of the air pressure the velocity from all openings will be substantially the Same.

With the use of the confined wind box with restricted, regulated, and correctly proportioned and distributed openings, nozzles or pipes, a pressure is built up in the box by the fan. This pressure causes a fixed head at each opening which forces the air coming out of the box and impinging on the heated surfaces to travel at a high and.

uniform velocity at each opening, nozzle or pipe. This high Velocity of air impinges on and sweeps or wipes the heated surfaces with which it cornes in contact, carrying away the lm of already heated air that has formed, and thus bringing the cold air into close intimate contact with the heated surfaces of the furnace. After the air has lost its velocity due to its loss of head by its expansion in the air chamber the velocity of the air becomes normal as in any other properly installed heating unit.

This arrangement assures all of the air coming into intimate contact with a heated surface and causes thel air to swirl and eddy, by means of which all of the air is diffused and mixed more thoroughly and stratification is avoided. Also, by reason of this distribution of the heat, excessive overheating of any part of the furnace structure can be Very definitely avoided, thus eliminating those conditions which tend to shorten the life of a warm air heating furnace.

What I claim is:

1. A warm air furnace comprising an inner furnace unit together with a radiator, an outer casing inclosing the heating units and spaced away from the units to provide an air circulating chamber, a flat horizontally placed wind box around the lower part of said inner heating unit, said wind box comprising a top and side portion together with a sloping side portion, said sloping side portion having a plurality of slotted openings so arranged as to discharge currents of air upwardly and inwardly against said inner heating unit and said top portion of said wind box having a plurality of slotted openings so positioned as to discharge currents of air upwardly against said,

radiator.

2. A warm air furnace comprising an inner furnace unit together with a radiator, an outer casing inclosing the heating units and spaced away from the units to provide an air circulating chamber, a flat horizontally placed wind box around the lower part of said inner heating unit, a shield mounted on said wind box and positioned between said outer casing andsaid inner furnace unit to intercept radiated heat, said wind box comprising a top and side portion together with a sloping side portion, said sloping sidey portion having a plurality of slotted openings so arranged as to discharge currents of air upwardly and inwardly against said inner heating unit and said top portion of said wind box having a plurality of slotted openings so positioned as to discharge currents of air upwardly against said radiator.

CARL B. LOCKI-IART. 

